The application of an argon/nitrogen inductively-coupled plasma to the analysis of organic solutions

A 4-kW argon/nitrogen inductively-coupled plasma (ICP) is used for multielement trace determinations in organic solutions. After optimization of the pneumatic nebulizer and ICP parameters, trace determinations at sub-mug/ml concentrations with relative standard deviations of 1% are possible. The first application described is the determination of a series of metals (Cd, Cu, Fe, Mn, Zn) after their isolation from the sample matrix by extraction of the ammonium pyrrolidinedithiocarbamate complexes into methyl isobutyl ketone. Alkali and alkaline-earth metal salts at 50-g/l. concentrations do not affect the method, which can be applied to trace determinations in industrial waste waters having high salt contents. The second application is the multielement analysis of oils. The samples are diluted 1:10 with xylene, and the detection limits for Al, Cu, Fe, Mg, Mn, Si and Zn are in the sub-mu/g range. The superior detection power of spectrographic ICP methods in comparison with photoelectric techniques using a monochromator and a polychromator is discussed. Oils of different viscosities can be analysed with use of the same calibration graphs. From experiments with a computer-controlled polychromator with background measurement facilities, it is concluded that the accuracy is improved if background measurements are made at wavelengths near the analytical lines, for each sample independently.     

Determination of differential heavy metal and trace element accumulation in liver, gills, intestine and muscle of sterlet (Acipenser ruthenus) from the Danube River in Serbia by ICP-OES

The accumulation of heavy metals in fish has been extensively studied and well documented. However, the research has been mainly focused on the muscle tissue, while the distribution patterns among other tissues, such as liver and gills, have been mostly neglected. Within the present study, the concentrations of Ag, Al, As, B, Ba, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Se, Sr, Zn and Li in the muscle, gills, liver and intestine of the sterlet (Acipenser ruthenus) from the Danube River have been assessed by using the inductively-coupled plasma optical spectrometry. The analysis has revealed a high degree of differential accumulation of the studied heavy metals and trace elements in the tissues of the Danube sterlet. Liver appeared to be the main heavy metal storage tissue, while the lowest levels of analyzed metals were found in muscles. Heavy metal concentrations in the muscle were at acceptable levels for human consumption, except partly for cadmium. We conclude that, in order to enable a more efficient control of contaminants in fish products, there is an apparent need to resolve the problem of lack of legal limits for many metals in European legislation.     

Development of a novel multi-element detection system for trace metal determination based on chemiluminescence after separation by ion chromatography

A highly sensitive, non-selective trace metal detector based on chemiluminescence has been developed. The metals, separated by simple ion-exchange chromatography, bring about the displacement of cobalt from a Co-EDTA post-column reagent. The liberated cobalt is then detected by the luminol-peroxide chemiluminescence reaction using a modified spectrofluorimeter as the detector. The metals determined are Mg, Ca, Sr, Ba, Fe(II), Fe(III), Co, Ni, Cu, Zn, the lanthanides, Th, Al, Ga, In, Pb and Bi. The detection limits (three times the baseline noise) range between 2 and 100 μg l^?1, depending on the analyte, for a 200-μl injection. To demonstrate the quantitative performance of the detector, the zinc and aluminium contents of a fresh water certified reference material was determined and gave good agreement with the certificate values.     

Voltammetric methods for speciation analysis of trace metals in natural waters

Trace metals play an important role in the regulation of primary productivity and phytoplankton community composition. Metal species directly affects the biogeochemical cycling processes, transport, fate, bioavailability and toxicity of trace metals. Therefore, developing powerful methods for metal speciation analysis is very useful for research in a range of fields, including chemical and environmental analysis. Voltammetric methods, such as anodic stripping voltammetry (ASV) and competing ligand exchange-adsorptive cathodic stripping voltammetry (CLE-AdCSV), have been widely adopted for speciation analysis of metals in different natural aquatic systems. This paper provides an overview of the theory of voltammetric methods and their application for metal speciation analysis in natural waters, with a particular focus on current voltammetric methods for the discrimination of labile/inert fractions, redox species and covalently bound species. Speciation analysis of typical trace metals in natural waters including Fe, Cu, Zn, Cd, and Pb are presented and discussed in detail, with future perspectives for metal speciation analysis using voltammetric methods also discussed. This review can elaborate the particular knowledge of theory, merits, application and future challenge of voltammetric methods for speciation analysis of trace metals in natural waters.     

采集的生物膜中痕量重金属的形态分布特征

采用改进的Tessier连续萃取方法对从松花江中采集的生物膜中锰、 铁、 铜、 铅、 锌及镉的化学形态进行分析, 考察了生物膜上铁、 锰氧化物和有机质吸附重金属的相对作用, 同时讨论了在研究培养的生物膜吸附痕量重金属时所建立的选择性萃取方法对于采集的生物膜组分分离的适用性. 研究结果表明, 在采集的生物膜上痕量重金属以铁、 锰的氧化物为主要结合形态存在, 以此种形态存在的铜、 锌、 铅和镉分别占其总含量的62.9%, 58.3%, 53.8%和32.6%, 而以有机结合态存在的铜、 锌、 铅和镉, 分别占其总含量的1.1%, 0.6%, 9.9%和1.8%, 表明采集的生物膜上铁、 锰氧化物在吸附重金属的过程中起主要的控制作用, 而有机质的作用相对较小, 与以往利用选择性萃取技术研究培养的生物膜吸附重金属的规律一致. 进一步分析表明, 如扣除生物膜上铁的残渣态部分, 则选择性萃取分离技术可以有效地将采集的生物膜上的铁、 锰氧化物及有机质分离开.     

Total reflection X-ray fluorescence and energy-dispersive X-ray fluorescence analysis of runoff water and vegetation from abandoned mining of Pb–Zn ores

The present work reports on the heavy metal content: Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Cd and Pb in running waters and vegetation around abandoned mining areas. Two species of mosses (Dicranum sp. and Pleurocarpus sp.) and three different species of wild grass (Bromus sp., Rumex sp. and Pseudoavena sp.) growing on the surrounding areas of old lead–zinc mines (Aran Valley, Pyrenees, NE Spain) have been analyzed. Both water and vegetation were collected in two different sampling places: (a) near the mine gallery water outlets and (b) on the landfill close to the abandoned mineral concentration factories. For the heavy metal content determination, two different techniques were used: total reflection X-ray fluorescence for water analysis and energy-dispersive X-ray fluorescence for vegetation study. Surface waters around mine outlets exhibit anomalous content of Co, Ni, Zn, Cd. Stream waters running on mining landfills exhibit higher Cu, Zn, Cd and Pb than those of the waters at the mine gallery outlets. The results allow us to assess the extent of the environmental impact of the mining activities on the water quality. The intake of these elements by vegetation was related with the sampling place, reflecting the metal water content and the substrate chemistry. Accumulation of metals in mosses is higher than those exhibited in wild grasses. Furthermore, different levels of accumulation were found in different wild grass. Rumex sp. presented the lowest metal concentrations, while Pseudoavena sp. reported the highest metal content.     

Trace metal accumulation in tissues of sole (Solea senegalensis) and the relationships with the abiotic environment

The distribution patterns and the organ-specific accumulation trends of 10 trace metals (iron, manganese, zinc, copper, chromium, nickel, cobalt, lead, cadmium and silver) and 4 major elements (sodium, potassium, calcium and magnesium) in 10 different tissues (heart, muscle, kidney, stomach, intestine, liver, gill, gonads, white skin and dark skin) of a benthic fish species (Solea senegalensis) from a densely populated coastal area affected by anthropogenic activities, the Bay of Cadiz (SW Spain), have been investigated. High variability of metal concentrations among tissues were found for Ca, Fe, Zn, Cu, Pb and Ag. Factor analysis was applied to study this variability. Five principal components were found explaining the 92.95% of the total variance and similarities in behavioural patterns of bioaccumulation were described. They associated Mg, Cr, Ni and Mn to intestine and stomach tissues (PC1), Ag, Cu and Cd to liver (PC2), Zn, K and Co to gonads (PC3), Na, Fe and Pb to gill, heart and kidney tissues (PC4) and Ca, Pb and Mn to gill and dark skin (PC5). The metallic concentration in the sediment and water was also studied. The pollution in this area was found moderate with outstanding values of Zn, Cu and Pb (average values of 139, 50.4 and 75.6?mg?kg^?1, respectively) in sediment and dissolved Cu (average value of 2.5?µg?L^?1). Metal bioconcentration trends followed the order Zn?>?Cu?>?Cd?>?Pb for dissolved metals in seawater, Cu?>?Zn?>?Cd?>?Pb?≈?Mn?>?Fe?≈?Ni?≈?Co for metals associated to particulate matter and Zn?≈?Cu?>?Cd?>?Mn?>?Co?≈?Fe?>?Ni?≈?Pb?>?Cr for metals in the sediment. Higher values were found for copper in liver, zinc in gonads and lead in gill, showing the relationship between biotic and abiotic environment. In addition, Cd bioconcentration factors were found high in liver and gill showing the sensitivity of sole to this metal even at low concentrations.     

Comparative study of heavy metal and trace element accumulation in edible tissues of farmed and wild rainbow trout (Oncorhynchus mykiss) using ICP-OES technique

The objective of this research was to determine the differences between farmed and wild rainbow trout in terms of heavy metal and trace element accumulation in edible tissues. The samples were analyzed for As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Se, Sr and Zn by inductively coupled plasma-optical emission spectrometry (ICP-OES); and for Hg by cold vapor atomic absorption spectrometry (CVAAS). The results were expressed as μg/g of dry weight. With the exception of Ba and Sr, liver had significantly higher heavy metal and trace element concentrations compared to the muscle in farmed or wild fish. Higher levels of Ba, Cr, Fe, Mn and Zn, as well as lower levels of Cu and Sr were found in tissues of wild rainbow trout compared to its farmed relative. Levels of Cd in 41.6% of farmed fish samples and 45.8% of wild fish samples exceeded the European Commission regulation. Regarding the Pb, concentrations in 50% of farmed fish samples and 62.5% of wild ones were above the European Commission limit. However, levels of Hg and As in all of the examined samples were lower than the legislated limits. The differences in heavy metal and trace element accumulation observed between farmed and wild fish were probably related to the differences in their environmental conditions and dietary element concentrations.     

Trace metal contents in certified reference sediments determined by nitric acid digestion and atomic absorption spectrometry

The trace metal (Cd, Cu, Pb, Zn, Fe) contents of certified reference sediments BCSS-1, MESS-1, SRM 1645 river sediment and SRM 1646 estuarine sediment) were determined by nitric acid digestion at 140°C without silicate lattice dissolution. All the metals studied except iron were completely recovered by this digestion method. About 20% of the iron was not recovered under the given conditions. The trace metal contents in SRM 1645 were also examined by using the hydroxylammonium chloride/acetic acid leaching procedure.     

Analysis of fish otoliths by electrothermal vaporization inductively coupled plasma mass spectrometry: aspects of precipitating otolith calcium with hydrofluoric acid for trace element determination

A method is developed for determination of trace elements, including Ag, As, Cd, Co, Cr, Cu, Mn, Ni, Se, Tl and Zn, in fish otoliths by electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS). Hydrofluoric acid was used to precipitate calcium resulting from acid dissolution of otolith calcium carbonate. Initial acidity of the sample solution influenced the precipitation efficiency of calcium fluoride. Up to 99.5% of Ca was precipitated in solutions that contained less than 2% (v/v) HNO₃. Recoveries of the elements obtained from spiked artificial otolith solutions were between 90 and 103%. Stabilization of the elements within the ETV cell was achieved with 0.3 μg Pd/0.2 μg Rh chemical modifier that also afforded optimum sensitivity for multielement determination. The method was validated by the analysis of a fish otolith reference material (CRM) of emperor snapper, and then applied to the determination of the trace elements in otoliths of several fish species captured in Raritan Bay, New Jersey. Results indicated that fish physiology and biological processes could influence the levels of Cu, Mn, Se and Zn in the otoliths of fish inhabiting a similar aqueous environment. Otolith concentrations of Cr and Ni did not show any significant differences among different species. Concentrations for Ag, As, Cd, Co and Tl were also not significantly different, but were very low indicating low affinity of otolith calcium carbonate to these elements.     

Determination of trace metals in seawater by an automated flow injection ion chromatograph pretreatment system with ICPMS

A novel flow injection ion chromatograph (FI-IC) system has been developed to fully automate pretreatment procedures for multi-elemental analysis of trace metals in seawater by inductively coupled plasma mass spectrometer (ICPMS). By combining 10-port, 2 position and 3-way valves in the FI-IC manifold, the system effectively increase sample throughput by simultaneously processing three seawater samples online for: sample loading, injection, buffering, preconcentration, matrix removal, metal elution, and sample collection. Forty-two seawater samples can be continuously processed without any manual handing. Each sample pretreatment takes about 10 min by consuming 25 mL of seawater and producing 5 mL of processed concentrated samples for multi-elemental offline analysis by ICPMS. The offline analysis improve analytical precision and significantly increase total numbers of isotopes determined by ICPMS, which include the metals Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Ti, V, and Zn. The blank value and detection limits of trace metals using the system with ICPMS analysis all range from 0.1 to 10 parts per trillion (ppt), except Al, Fe, and Zn. The accuracy of the pretreatment system was validated by measuring open-ocean and coastal reference seawater, NASS-5 and CASS-4. Using the system with ICPMS analysis, we have obtained reliable trace metal concentrations in the water columns of the South China Sea. Possessing the features of full automation, high throughput, low blank, and low reagent volume used, the system automates and simplifies rigorous and complicated pretreatment procedures for multi-elemental analysis of trace metals in seawater and effectively enhances analytical capacity for trace metal analysis in environmental and seawater samples.     

Partitioning of metals between the aqueous phase and suspended insoluble material in fog droplets

This paper discusses the partitioning of metals (K, Na, Ca, Mg, Al, Cu, Fe, Pb and Zn) between the aqueous phase and the suspended insoluble material in fog samples collected in the Po Valley during two extensive fields campaigns. Metals represent on average 11% of the mass of suspended insoluble matter, while the main component is carbon (both organic carbon, OC = 35%, and black carbon, BC = 8%). The unaccounted suspended matter mass is very high, on average 46%, and is attributable to non metallic species, such as O and N and of Si. The principal metals in the insoluble suspended fraction are Fe and Al (2-5%), while the contributions of other metals (Na, Mg, Cu, Pb and Zn) are lower than 1%. Ca and K exhibited high blank values and could not be detected above blank detection limit threshold. The main components in the aqueous phase are NO3- (34%), WSOC (23%), SO4(2-) (18%) and NH4+ (19%), while trace metals and remaining cations and anions accounted for less than 1% of solute mass. The main dissolved trace metals in fog droplets are Zn, Al and Fe, while the main metallic cations are Na and Ca. Fe and Al are the only metals preferentially distributed in the suspended insoluble matter of fog droplets (partitioning ratio respectively 37% and 33%). All other metals are mostly dissolved in the aqueous phase (mean partitioning ratios of Mg, Pb, Zn, Cu and Na are 69%, 70%, 77%, 81% and 87%). These findings are in agreement with literature data on metal speciation in cloud and rain samples. The dependence of partitioning ratios on pH is investigated for the different metals, with only Al showing a clear partitioning ratio decrease with increasing pH. Conversely, the other metals show no dependence or a complex and highly variable behaviour. The partitioning ratio of iron (mean 37%) observed in the Po Valley fog samples is much higher than the water extractable iron in aerosol particles (typically 1-2 %): this fact can be explained by differences in the aerosol sources and composition among sites and by chemical processes in the aqueous phase, such as complexation and redox reactions involving organic ligands (oxalate, or other organic acids as humic-like organic matter) which may promote Fe solubility.     

Depth Profiling (ICP-MS) Study of Trace Metal ‘Grains’ in Solid Asphaltenes

Knowledge of trace metal ‘grains’ in asphaltenes could play a significant role in enhancing refining and processing of crudes and also in providing useful information on mechanistic and migratory features linked to asphaltenes. These metals originate directly from interaction of oils with source-rock, mineral matter, and formation water and their accumulation in asphaltene matrices could vary from oil well to oil well. Suitable asphaltene samples were subjected to high-performance ICP-MS laser depth profiling (213 nm) to depths of 50 μm at 5 μm intervals. The study was conducted in the absence of standardization and characteristic intensities originating from the metals of interest were measured. Ten metal profiles were investigated (Na, Mg, Al, Mn, Fe, Zn, Sr, Pb, V, and Ni). The experimental results showed non-uniform distribution of trace metals and identified areas where such metals agglomerate. The data suggested that certain chemical and physical conditions within the structure of asphaltenes are favorable for metal ‘grain’ formation at specific points. The exact mechanism for this behavior is not clear at this stage, and has considerable scope for future studies, including mathematical modeling simulations of asphaltenes. We also found that solid asphaltenes could be a useful forerunner of scale formation.     

Trace metal concentrations in single specimens of the intestinal broad flatworm (Diphyllobothrium latum), compared to their fish host (Oncorhynchus mykiss) measured by total reflection X-ray fluorescence spectrometry

The aim of this study was to investigate (1) whether intestine endoparasites (Diphyllobothrium latum) accumulate trace elements related to its body size and (2) whether parasites bioconcentrate more trace elements than their host. Freshwater fish (rainbow trout Oncorhynchus mykiss) were sampled in the deep, oligotrophic and uncontaminated Lake Riñihue in Southern Chile. The element concentration of different organs (intestine, muscle, liver) and of the intestine endoparasites were analyzed using total reflection X-ray fluorescence spectrometry. The results showed that the mass fraction for Mn, Fe, Ni, Cu, and Pb decreased significantly with the body size (dry weight) of the endoparasite. Only Zn did not reveal such a relationship. Small parasites accumulated up to 80 times more Fe, Ni, Mn, Pb, and Cu than large parasites. Compared to the fish organs, small parasites accumulated in maximum 35 to 307 times more Mn, 5 to 255 times more Fe, 98 to 220 times more Ni, 3 to 175 times more Cu, and 0.4 to 12 times more Zn than the fish. Lead was only found in the endoparasite, but not in the fish organs. We conclude that (1) D. latum is a good indicator for trace element accumulation in fishes and that (2) small endoparasites are more sensitive as bioindicators because they showed higher bioconcentrations of trace metals than larger parasites.     

Influence of the physical properties and handling of silica gel modified carbon paste electrodes on the phase transfer of solved Cu(II) ions

EDTA, a powerful chelating agent, is used extensively in soil sciences to determine the bioavailability of trace metals and their possible decontamination from polluted soils. Because of its non-selective nature, the co-dissolution of major elements also occurs, in addition to the extraction of trace metal ions.In this work, the reactivity of trace and major elements (Pb, Cu, Cd, Al, Fe, Ca and Mg) with different concentrations of EDTA was studied in eight soil samples (Burgundy, France). The limit between lack and excess of EDTA with respect to total metal extracted, determined after 24 h of reaction for different types of soil varied from 0.002 to 0.05 M, respectively.For calcareous samples the amount of Pb, Cu and Cd extracted by EDTA was reduced to 50% of that extracted in non-calcareous soils.From the kinetic point of view, the extraction behavior of major elements seemed to depend heavily on excess or lack of EDTA and the soil Ca content. For a lack of EDTA, different competitive behaviors were revealed for the major elements (Al, Ca, Fe and Mg) towards the reagent, depending on the soil matrix.According to these experimental results, the mass balance between the reagent and cations in any EDTA-soil media is strongly controlled by major metal extraction. When choosing the reagent concentration needed to extract the trace metals efficiently, all the extractable metal present in the concerned sample must be taken into account.     

微波消解ICP-AES法测定贝类中微量元素的含量

采用硝酸-过氧化氢作为消解液对样品微波溶样,应用电感耦合等离子体发射光谱法(ICP-AES)分别对湛江市场8种贝类中的Zn、Cd、As、Fe、Cr、Cu等6种微量元素进行测定。结果表明,贝类种类之间对重金属的累积存在明显差异,这些贝类都有部分甚至全部元素超过了相关限量的情况存在,应引起有关部门高度重视。     

Utilization of optimized BCR three-step sequential and dilute HCl single extraction procedures for soil-plant metal transfer predictions in contaminated lands

The prediction of soil metal phytoavailability using the chemical extractions is a conventional approach routinely used in soil testing. The adequacy of such soil tests for this purpose is commonly assessed through a comparison of extraction results with metal contents in relevant plants. In this work, the fractions of selected risk metals (Al, As, Cd, Cu, Fe, Mn, Ni, Pb, Zn) that can be taken up by various plants were obtained by optimized BCR (Community Bureau of Reference) three-step sequential extraction procedure (SEP) and by single 0.5 mol L(-1) HCl extraction. These procedures were validated using five soil and sediment reference materials (SRM 2710, SRM 2711, CRM 483, CRM 701, SRM RTH 912) and applied to significantly different acidified soils for the fractionation of studied metals. The new indicative values of Al, Cd, Cu, Fe, Mn, P, Pb and Zn fractional concentrations for these reference materials were obtained by the dilute HCl single extraction. The influence of various soil genesis, content of essential elements (Ca, Mg, K, P) and different anthropogenic sources of acidification on extraction yields of individual risk metal fractions was investigated. The concentrations of studied elements were determined by atomic spectrometry methods (flame, graphite furnace and hydride generation atomic absorption spectrometry and inductively coupled plasma optical emission spectrometry). It can be concluded that the data of extraction yields from first BCR SEP acid extractable step and soil-plant transfer coefficients can be applied to the prediction of qualitative mobility of selected risk metals in different soil systems.     

Histidine as the functional group for a chelating ion exchanger

In the chelating ion exchanger synthesized, the amino group of histidine is attached chemically via the azide method to the carboxyl group of Amberlite IRC-50. A flow system based on a spectrophotometric detector, with 4-(2-pyridylazo) resorcinol as reagent, is described for fast assays of eluted cations. The pH dependence of the metal extraction is reported for Ag(I), Au(III), Cu(II), Fe(III), Hg(II), Ni(II) and Zn(II) ions. The resin exhibits no affinity for the alkali or alkaline earth metals. The uptake of traces of the specified elements from synthetic samples by a short (90 mm) column of the histidine-containing resin was in the range 94–100% and the retained metals were readily eluted by means of 2 M hydrochloric or hydrobromic acid. In column operation, mercury was quantitatively recovered even in the presence of large excesses of various ligands. The recoveries of the trace metals were good at the usual pH of natural waters.     

Analysis of fish samples for environmental monitoring and food safety assessment by synchrotron radiation total reflection X-ray fluorescence

Summary This study uses fishes as indicators of metal contamination in the Piracicaba Basin and also for evaluation of the risks to human health by the ingestion of fish contaminated by metals and other potentially toxic elements. Based on total reflection X-ray fluorescence analysis, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn and Ba were detected and evaluated in the muscle and viscus (liver, intestine and stomach) of fish collected in the Piracicaba River.     

Evaluation of humic complexes of trace metals in river water by adsorption on indium-treated XAD-2 resin and DEAE-Sephadex A-25 anion exchanger

A combined adsorption procedure for the analytical fractionation of humic/metal complexes in river water is described. It is based on an indium-loaded XAD-2 resin and a DEAE-Sephadex A-25 anion exchanger, respectively. After the separation of suspended particles, an aliquot of the water sample to be analysed is passed through an indium-loaded XAD-2 resin column to collect the metal-humic complexes. A second aliquot is directly passed through a DEAE-Sephadex A-25 anion exchanger column to collect humic complexes and other negatively charged metal species. Both column effluents are analysed by inductively coupled plasma-mass spectrometry or by graphite-furnace atomic absorption spectrometry for various trace metals (e.g., Al, Mn, Fe, Co, Ni, Cu, Zn, Sr, Ba). According to this fractionation procedure, significant amounts of iron, aluminium and copper in river water are found to be humic complexes, and less than 15% of nickel, cobalt and zinc are complexed with humic substances. Manganese, strontium and barium are hardly associated with humic substances.